https://programmers.co.kr/learn/courses/30/lessons/68644
단순 구현 문제
def solution(numbers):
answer = []
temp = []
for i in range(len(numbers) - 1):
for j in range(i + 1, len(numbers)):
temp.append(numbers[i] + numbers[j])
answer_set = set(temp)
answer = list(answer_set)
answer.sort()
return answer